Dengue count Sri Lanka: 2017; the worst year on record?

Stop Press:  Dengue Cases 2017: January – July: 101,698 ( figures update monthly)

Total dengue cases 2016:  54,945 (2015: 29,777)
Sri Lanka recently announced it has eradicated Malaria from the island; no mean feat. So why not Dengue fever? Both are viral infections carried by mosquitoes. Sri Lanka has ambitious plans to develop its economic base and to establish the Western Province (based around Colombo) as a major business hub for South Asia; see The Megapolis plan elsewwhere on Geosrilanka (click here). But, has the government got its priorities round the wrong way. Should improving public health come first? There is no organised garbage collection, what there is, is privatised;  (a major source of mosquito breeding sites), fly tipping is commonplace, there is no real investment in dengue protection and prevention; and there is an almost complete lack of regulation of buildings, companies and individuals who seem to be able to flout what laws there are.  Maybe what it really needs is for several high profile politicians to contract dengue or worse still dengue hemhoraggic fever or DHF ( a killer) before the government acts. Make no mistake , the more cases of dengue there are overall the more potentially fatal cases of DHF.. that’s just basic mathematics!
But don’t think this is an internal issue; Part of the economy is built on the revenue from tourism. The warning signs re tourism are beginning to go up. Just check out travel advisories. At the moment there are quite low key but they will ramp up and tourists will go elsewhere. Right now, health wise Colombo is not a great place to be at least to a potential tourist. Will foreign businesses really want to locate new offices in a country which seems incapable of dealing with this threat? Anyone who has contracted dengue will tell you; it is a very nasty disease; not just a cough/cold..and then there are related viral infections like chickungunya..so instead of sitting on their hands is it time for the authorities to step up to the plate?

In an earlier article I asked the question; Is Sri Lanka winning the war against dengue? Well the place to go to get the answers is the Ministry of Health Epidemiology Unit. The answer would seem to be “absolutely not”.. take a look.

2016 was a very bad year, in fact until now the worst year on record. What made it so disappointing was that in 2015 the number of cases island wide was down to under 30,000 so there was hope that a  corner had been turned in the battle against dengue fever; but it hadn’t. The number of cases almost doubled.

Worryingly 2017 has been even worse. So far in 2017 ( up to end June ) there have been over 100,000 reported cases; already more than what was a record year in 2016. Things are getting much much worse! What it also points to is that this year (2017) the figure will most likely top 150,000 cases!

This should be a major cause for concern

Up until 2017 an analysis of the data  shows is that the number of reported cases used go up and down; one year up the next down,see below; figures are for all Sri Lanka 2010 – 2016.

dengue-sl-2010-2016

Even so, as you can see the overall trend line is up! But now in 2017, there isn’t even the respite of a dip in cases.

The Yo Yo effect

Why should the figures fluctuate the way they do? At present no-one can definitively say why, it seems. There could be a number of factors; climatic variations being one suspect.

  • Studies in Singapore link  dengue outbreaks to particular temperature regimes.  As temperatures rise beyond 25deg the incubation period for the mosquito shortens.. populations grow rapidly and the feeding rate increases.  Currently the Singapore authorities use an ambient temperature of 27.8 degrees as a baseline and issue warnings when it goes above this figure..so possibly the same applies to Colombo. Relatively minor changes in ambient temperature may help to explain the variation at least in part. Research is needed to substantiate this, however.
  • Heavy rain affects the survival rate of the larvae.. they get flushed out of their breeding areas.. especially if it is continuous and prolonged. It is actually the period after the rains when there is still standing water around that the mosquitos can breed rapidly.. so an in depth analysis of rainfall patterns and  disease outbreak patterns is probably needed ( bear in mind that there is a 1 to 2 month time lag between peak rainfall and the upsurge in cases )
  • the virus itself seems to change; two serotypes in particular, of the virus appear to alternate; some years it is S1 and then after a period S1 seems to decline in impact to be replaced by S2
Of real interest however is the report of the re-emergence of the S2 strain of the virus
The emergence of a new serotype

note: a serotype is is a distinct variation within a species of bacteria or virus

There are 4 serotypes of the dengue virus; types 1,2,3 and 4. As I understand it over time populations can develop some degree of immunity to any one strain. But, immunity to say type 1 does not give immunity to the other three types. So if a new strain or serotype of the virus emerges it is likely that the population doesn’t have an immnunity and so the number of cases surges upwards.

I found this on the facebook page of the Centre for Dengue Research based at Sri Jayawardenepura University

The sudden rise in 2009 was (the) emergence of dengue 1, the current increase is because of (the) emergence of serotype 2 which was not around for 6-7 years. (The) Question is why do serotypes suddenly appear and then disappear? The $64000 question perhaps!

Understanding the way the virus works seems to be a long way off. That makes it doubly important to control the mosquito vector by destroying it’s breeding sites

Dengue Hotspots
  • Colombo          21,732
  • Gampaha         11181
  • Jaffna                3216
  • Galle                 3475
  • Kalutara            5586
  • Batticaloa         4135
  • Trincomalee      4415
  • Kurunegala       4700
  • Ratnapura         6073

In 2016 Batticaloa and Trincomalee reported less than 1200 cases between them. This year the East coast seems to be suffering a dengue epidemic! But then so does Kurunegala and Ratnapura

But in any case everywhere is showing an increase, with Western province responsible for 42% of all notified cases

The main reasons given are all too familiar:

  • a lack of co-ordination between local authorities; between the ministries for health, environment and education; problems in enforcing anti-mosquito breeding action;
  • a lack of dengue-awareness raising programme
  • poor or non existent garbage collection and disposal
  • understaffing of public health departments
  • general indifference on the part of the government, politicians and the public.
1.  Colombo/Kalutara/Gampaha Hotspots

Western province is a major hotspot with over half of all dengue cases. Colombo  Gampaha and Kalutara now account for 41% of all cases; rising from less than 25% in 2010. There are a number of reasons why this might be; below is the graph for Colombo.

colombo-dengue

(Note: the curve for Colombo is different.. less of a yo-yo effect)

  1.  Colombo Gampaha and Kalutara  are in the Wet Zone; hot wet and humid all year the region provides the ideal climate for mosquitos to breed.
  2. The Western Province is the most densely populated and most urbanised region in the country.
  3. The aedes egypptii mosquito that carries dengue is well adapted to urban areas and thrives where there are:
  • piles of garbage left uncollected in the street
  • coconut husks and old tyres left lying around
  • well watered gardens and water pots
  • rubbish clogged canals
  • broken or poorly maintained drainage pipes and storm drain outlets
  • building sites where there is standing water, piles of rubbish and no real regulation to ensure monitoring of potential mosquito breeding sites
  • small tracts of undeveloped land which quickly become breeding sites for mosquitoes

3.  large areas of Colombo are high density; especially the underserved settlements. So it is quite easy for dengue to spread once it takes hold in an area

4.  high levels of construction activity; this is new but since 2009 when the civil war was brought to an end the  rate of new construction has increased exponentially, and construction sites provide ideal sites for mosquitos to breed:

  • untended rubbish,
  • standing water
  • lack of pest control
  • a large number of nooks and crevices.

Indeed there are allegations that local governments and municipal councils are directly responsible for many of the largest mosquito breeding areas. There have been frequent protests against the creation of large uncovered garbage dumps near residential areas and the failure to clean stagnant canals, sewerage sites and other pits and potholes filled with polluted water.

Dengue control and prevention is a duty of the local authority. The Public Health Department of the Colombo Municipal Council  should have around 55 Public Health Inspectors, 150 Midwives, 185 Health instructors, 55 Mosquito control Field Assistants, who could have been used to inspect all the premises and land parcels in the city which number around 80,000. Unfortunately, instead of these 450 Field Officers, there are only around 180 to do this work. (according to Dr. Pradeep Kariyawasam Former Chief Medical Officer of Health, Colombo in an article in “The Island” newspaper. (May 2nd).

He adds that in the past there was an organised control programme of fogging and spraying potential mosquito nesting sites but this programme has lapsed  “due to some unknown reason.”

“Only the interiors of houses are sprayed, when 95 % of the breeding takes place outside the four walls. The PHIs in the suburbs also have copied Colombo’s above idea, and this may be one reason why we have so many dengue mosquitoes and patients today. Even the inspections have been done only when Mosquito control weeks have been announced by the Ministry of Health”.

He goes on to explain that one of the problems was that control programs could not be started at the proper time. “The dengue mosquito’s flying range is only 100-200 metres. So if we could start our control and education programs early it would be easy to reduce casualties.”

Kariyawasam added: “The biggest problem we face is a lack of manpower as a result of not recruiting people for 10 to 15 years. We do not have a single entomological assistant. We need at least 50 public health inspectors but we have only 23 now. We have only 22 field assistants to cover the work of 75. We employ only 70 health instructors though we need 150.

“Our budget does not allow us to communicate our educative messages in the electronic media and press. TV companies charge 20,000 rupees per 15 seconds. A one-page newspaper advertisement costs 100,000 rupees. Even in the state-owned media we do not get a chance.”

The situation has worsened as council services have been privatised. A resident in the Sri Jayawardanapura municipal council area told the WSWS: “After the cleaning services were privatised, the number of sanitary workers has been further reduced and we have to keep our garbage for several days until someone comes. The spraying of insecticides for mosquitoes has been halted or curtailed. I have not seen any spraying for several months.”

In a recent Daily Mirror article the paper criticised local government for not organising a  more effective clean up campaign but they also pointed out ;

  1. poor management of construction sites (the Colombo Municipal Office  has issued 70 red notices  closing down building sites in contravention of mosquito control laws)
  2. workplace and school place locations have seen a noticeable increase in breeding sites

this comment from the paper: “The situation cannot be a surprise considering the deterioration of cleanliness in major towns in the recent past for which even President Maithripala Sirisena had reprimanded the relevant minister last year.”

and they add

“The health authorities who always rightly advise the general public to remove their garbage in a regular manner do not seem to have taken note of the lethargic attitude of the local authorities who are mainly responsible for garbage disposal.”

What made the whole situation worse for Colombo last year. were the floods which inundated large areas around the Kelani river in May They left behind a mess of mud, garbage and standing water which went uncleared for a significant period and which would have provided ideal breeding grounds for the mosquito to thrive.

Jaffna and Galle

And now Jaffna is becoming a hotspot; the last 3 years have shown significant increases! (only I peak here to coincide with the North-East Monsoon otherwise pretty low during the dry season when the mosquitos are less likely to be breeding.)

  • 2014       1839
  • 2015       2016
  • 2016       2468 a net % increase of 34% on 2015
  • 2017       2998 to end June

nb; * in 2011 there were only 400 recorded cases all year;

If we assume that the number of dengue cases May to December matches 2016 then we can expect another 1400 cases. 2017 could see 3500 cases registered in Jaffna; that is a massive 37% increase once again.

So why is the number of cases increasing so fast in Jaffna? It seems likely that dengue has been “imported” in to Jaffna. Prior to 2009 movement in and out of Jaffna was probably quite tightly restricted  first by the Tamil Tigers and then by the Sri lankan government; but now Jaffna is opening up. Now more and more people are visiting including a number from Colombo, and they are most likely bringing the virus with them.

NB; the recent floods and the resultant standing water. left behind will most likely have been a contributory factor.

Galle is also showing an uptrend

  • 2014       1224
  • 2015       1030
  • 2016       3083    an increase of over 250%
  • 2017       2919 to end June

Galle seems to be bucking the trend to some degree but in the same period last year there were only around 600 reported cases ; there was a large spike in December. So for Galle it is too early to judge

nb; there were just 879 recorded cases in 2011

the disease incidence  follows the pattern of Colombo: two peaks June and January. So although the figures for Galle are lower overall, the increases over the past 4 years are worrying.

Speaking with a researcher working in the Galle area, recently,  she suggested that one of the reasons could be that the villages in the Galle area are becoming quite urbanised. Maybe it is also the case that the highway has increased the number of visitors coming from and going to Colombo

Urgent Action Needed ( suggestions from Dr. Pradeep Kariyawasam )

1) Employ dedicated staff (2 officers with at least 2 volunteers)  for around 50-75 premises in a street, who will meet the residents, create awareness and check these same premises and lands throughout the year. They will know exactly where to look for mosquito breeding in their allocated area, as it is difficult to find the larvae which could breed in one teaspoon full of water. . This is far better than sending officers to unknown terrain to look for breeding spots which will be fruitless.

2) All vacancies for PHIs, Midwives, Health Instructors and Field Assistants should be filled immediately.

3) The stopped chemical/BTI spraying programmes should be re-started. The internal spraying should be stopped as that strategy is used in Malaria control where the mosquitoes rest inside the houses. This internal spraying will cause more harm than good as the residents will be breathing the chemicals and that could create respiratory diseases, and also the food could be contaminated.

4) The shramadana programmes of yesteryear should be re started as soon as the waste dumping issue is settled in the country. This is very important in slum and shanty areas in the city, where 60% of the city’s population live.

5) All yards and bus stands, where public transport vehicles are parked, should be fumigated and kept clear of mosquito breeding places.

Data Source

The Epidemiology unit is an excellent source of current and past data on dengue fever; you can find it at http://epid.gov.lk/web/index.php?option=com_casesanddeaths&Itemid=448&lang=en#

It isn’t so much that Sri Lanka has turned the corner in the fight against dengue.. far from it. The question really is; have the authorities even joined the fight? There are 2 articles from The Sunday Times which are quite damning of the current situation and are well worth a read.

  1.  Dengue sites need to be cleared with ‘military precision’  this one starts with this sentence; says it all “Official lethargy and public indifference are the two major obstacles in the way of checking the spread of dengue fever around the country, health officials say as dengue continues to rise ”

    2.  Authorities despair at public unconcern over dengue

Vaccine Trials

The Sunday Times in Sri Lanka 01/05/16 has reported that Sri Lanka has agreed to take part in field trials for a vaccine that has the potential to provide protection against all 4 strains of the dengue virus; great news which provides some hope for the future at last but clinical trials have recently begun and although early results are promising a vaccination could be years down the line. In there meantime….

Dengue fever is nasty. Just because it doesn’t kill that many people is no reason to ignore it or take a fatalistic view. People get sick, spend time off work, lose income and some plain die. It seems crazy that people have to be taken to court and fined before they will take simple steps to keep the mosquito at bay.

and one last thought; if a new vaccine becomes available will people stop taking the precautions, that some now ignore, altogether? Viruses typically mutate over time..

If Malaria can be effectively contained why not dengue?

Headline Image; credit: Ellen Forsyth

 

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